Key Points

His cap-and-trade plan for fighting climate change calls for gradual reductions in U.S. greenhouse-gas emissions from utilities, transportation fuels, and large businesses, with a target of cutting emissions to 1990 levels by 2020, and 60 percent below 1990 levels by 2050.

Cosponsored the first bill in the Senate calling for mandatory reductions of greenhouse-gas emissions, in 2003. The 2007 version, the Climate Stewardship and Innovation Act, is less stringent than many other climate bills currently in Congress. It would cap global-warming emissions from utilities, industry, and transport at 2004 levels by 2012 and then gradually decrease emissions to about 30 percent of 2004 levels by 2050.

Has been an outspokencritic of the Bush administration’s lack of action against climate change.

Believes the U.S. should embrace nuclear power as a way to generate energy without directly producing greenhouse-gas emissions. His climate plan would take some of the money raised from auctioning emission allowances and make it available for nuclear power R&D.

In April 2008, began advocating for a summer “gas-tax holiday” to ease consumer prices at the pump. The proposal would suspend the 18-cent federal gasoline tax and 24-cent diesel tax from Memorial Day to Labor Day and cost the government some $10 billion.